const fs = require('fs-extra');
const unified = require('unified');
const parse = require('remark-parse');
const parse2 = require('rehype-parse');
const rehype = require('remark-rehype');
const stringify = require('rehype-stringify');
const stringify2 = require('remark-stringify');
const remark = require('rehype-remark');
const path = require('path');
const readDirP = require('readdirp-walk');
const {
    Translate
  } = require('@google-cloud/translate');


const lang = 'es';
const langFull = 'spanish';

const mdProcessor = unified()
  .use(parse)
  .use(rehype, { allowDangerousHTML: true })
  .use(stringify);

const htmlProcessor = unified()
  .use(parse2)
  .use(remark)
  .use(stringify2);

readDirP({
    root: path.resolve(__dirname, `./test`)
  })
  .on('data', translateChallenge);

async function translateChallenge(file) {
  const {
    name,
    depth,
    path: filePath,
    fullPath,
    fullParentDir,
    stat
  } = file;
  if (stat.isDirectory() || name === '.DS_Store' || file.depth == 1) return null;

  
  const pathIndex = fullPath.indexOf('guide') + 6;
  const outputDir = fullParentDir.substring(0, pathIndex) + `${langFull}/` + fullParentDir.substring(pathIndex + 5);
  const outputPath = fullPath.substring(0, pathIndex) + `${langFull}/` + fullPath.substring(pathIndex + 5);
  if (fs.existsSync(outputPath)) return null;
  fs.ensureDirSync(outputDir);

  const fileString = fs.readFileSync(fullPath).toString();
  var i = fileString.indexOf('---', 4)
  const meta = fileString.substring(0, i+4)
  const title = fileString.split('\n')[1].split(': ')[1];
  var article = fileString.substring(i+4)
  
  mdToHtml(article).then((htmlArticle) => {
    htmlArticle = htmlArticle.replace(/\n/g, '<br>')
    htmlArticle = htmlArticle.replace(/        /g, '&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;')
    htmlArticle = htmlArticle.replace(/    /g, '&nbsp;&nbsp;&nbsp;&nbsp;')
    htmlArticle = htmlArticle.replace(/  /g, '&nbsp;&nbsp;')
    translate(htmlArticle, title, meta, outputPath);
  })
}

function translate(htmlArticle, title, meta, outputPath) {
    Promise.all([
        translateText(title),
        translateText(htmlArticle)
      ]).then(function(translations) {
        // Replace English with translation
        let translatedTitle = translations[0][0];
        let tempArticle = translations[1][0]
        tempArticle = tempArticle.replace(/<br>/g, '\n')
        tempArticle = tempArticle.replace(/&#39;/g, `'`)
     
        // tempArticle = tempArticle.replace(/language-html">/g, 'language-html">\n')
        // tempArticle = tempArticle.replace(/<pre> <code/g, '<pre><code')
        // tempArticle = tempArticle.replace(/<\/code> <\/pre/g, '</code></pre')
        tempArticle = tempArticle.replace(/&nbsp;/g, ` `)

        htmlToMd(tempArticle).then((translatedArticle) => {
            const i = meta.indexOf('---', 4);
            let translatedFile = meta.slice(0, i) + `localeTitle: ${translatedTitle}\n` + meta.slice(i) + translatedArticle;
            writeFile(translatedFile, outputPath);
        });
      });
}

const createTranslateText = target => (text) => {
    if (!text) return '';
    const translate = new Translate();
    
    return translate
        .translate(text, target)
        .then(results => {
        let translations = results[0];
        translations = Array.isArray(translations) ?
            translations : [translations];
        return translations;
        })
        .catch(err => {
        console.log(err);
        });
}
    
const translateText = createTranslateText(lang);


function writeFile(fileString, outputPath) {
    fs.writeFile(outputPath, fileString, function(err) {
        if (err) throw err;
        console.log('Saved:' + outputPath);
      });
}

function mdToHtml(file) {
    return new Promise((resolve, reject) =>
      mdProcessor.process(file, function(err, file) {
        if (err) {
          reject(err);
        }
        return resolve(file.contents);
      })
    );
  };
  
  function htmlToMd(file) {
      return new Promise((resolve, reject) =>
        htmlProcessor.process(file, function(err, file) {
          if (err) {
            reject(err);
          }
          return resolve(file.contents);
        })
      );
    };